Flooding effects on abundance of an exploited, long-lived fish population in river-floodplains of the Amazon

Castello, Leandro; Bayley, Peter B.; Fabré, Nidia Noemí; Batista, Vandick da Silva

doi:10.1007/s11160-019-09559-x

Cited by 37 publications

(27 citation statements)

References 46 publications

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“…Nyahongo et al, 2009), often exacerbated by anthropogenic changes to ecosystems (e.g. Castello, Bayley, Fabré, & Batista, 2019), we may be overlooking food instability in wild food systems, which is potentially very common and dangerous for human health (Ferro‐luzzi et al, 2001). Food security measures should therefore be considered alongside ecological monitoring in order to achieve sustainable exploitation of wildlife and food stability, particularly during lean periods.…”

Section: Discussionmentioning

confidence: 99%

Tough fishing and severe seasonal food insecurity in Amazonian flooded forests

2020

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1. Billions of people rely on harvesting wildlife for food, and must contend with catch rates that vary in space (e.g. overharvesting near communities) and time (e.g. seasonal migrations). Yet, research has overlooked potential linkages between reduced wildlife catch rates (catch-per-unit-effort) and food security. Moreover, assumptions that people living in biologically rich environments are food secure lack empirical testing. This is problematic given that food security rests on having stable access to sufficient food, rather than there being sufficient food.2. We examine spatiotemporal variation in fish catch rates and perceived food security among rural communities in Amazonian flooded forests. We also assess social inequities in food insecurity. We used structured interviews to collect data on fishing, hunting, chicken and beef consumption, and perceptions of food security.We did so during 556 household visits along a spatial gradient (1,267 km) of commercial fishing pressure, during high-and low-water seasons.3. We provide the first empirical evidence of simultaneous seasonal crashes in wildlife catch rates and food insecurity. During the high-water season, fish catch rates were 73% lower, and the probability of not eating for a whole day was four times higher. With a third of households skipping meals and a sixth not eating for a whole day during this season, food security can be classed as severe. However, less-deprived households tended to avoid severe food insecurity. Fish catch rates and perceived food security did not vary along a spatial gradient of commercial overfishing. River-dwelling Amazonians increased fishing and hunting efforts during the high-water season, without eating more chicken and beef, emphasizing the importance of stable access to wild fish and bushmeat.4. This study shows how wildlife catch rates and food security can crash seasonally and simultaneously, demonstrating the fallacies of environmental and social policies which assume stability of food availability in resource-rich areas. Our results have implications for degraded habitats where falls in catch rates also occur. This suggests that overharvesting, as with other causes of reduced catch rates, could cause food insecurity in wildlife-reliant populations. | 469People and Nature TREGIDGO ET al.

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Section: Discussionmentioning

confidence: 99%

Tough fishing and severe seasonal food insecurity in Amazonian flooded forests

2020

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“…By reducing variability, intensity, and amplitude of the downstream flood pulse, and by modifying geomorphology, dams also disrupt lateral connectivity between river channels and floodplains (Forsberg et al, 2017). Migratory fishes that seasonally migrate laterally to floodplain habitats then have fewer opportunities to colonize flooded forest habitats that play key roles as nursery and feeding areas, ultimately affecting fisheries (Castello, Bayley, Fabré, & Batista, 2019; Castello, Isaac, & Thapa, 2015). For example, a 37% reduction in maximum flooded area in the Loreto Region, Peru, following the construction of large dams would result in an 88% decline in annual fish yield (Forsberg et al, 2017).…”

Section: Threats To Migratory Species In the Amazon Basinmentioning

confidence: 99%

“…There are now ~500 fishing communities implementing CBM for Arapaima in the Amazonas state alone (Campos‐Silva, Hawes, & Peres, 2019). Where studies have been made, populations of Arapaima and of other migratory species have recovered from overexploitation by increasing abundance (Campos‐Silva et al, 2019; Campos‐Silva & Peres, 2016; Castello et al, 2019). Catch per unit effort is also generally higher in lakes with CBM than in lakes without, as is mean body length of target species, including long‐distance migratory species, even though these management schemes are at the small, local scale (Almeida, Lorenzen, & McGrath, 2009; Castello, Stewart, & Arantes, 2011).…”

Section: Challenges In Research Management and Conservationmentioning

confidence: 99%

Conservation of migratory fishes in the Amazon basin

Duponchelle

Isaac

Doria

et al. 2021

Aquatic Conservation

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The Amazon basin hosts the Earth's highest diversity of freshwater fish. Fish species have adapted to the basin's size and seasonal dynamics by displaying a broad range of migratory behaviour, but they are under increasing threats; however, no study to date has assessed threats and conservation of Amazonian migratory fishes. Here, the available knowledge on the diversity of migratory behaviour in Amazonian fishes is synthesized, including the geographical scales at which they occur, their drivers and timing, and life stage at which they are performed. Migratory fishes are integral components of Amazonian society. They contribute about 93% (range 77–99%) of the fisheries landings in the basin, amounting to ~US$436 million annually. These valuable fish populations are mainly threatened by growing trends of overexploitation, deforestation, climate change, and hydroelectric dam development. Most Amazonian migratory fish have key ecological roles as apex predators, ecological engineers, or seed‐dispersal species. Reducing their population sizes could induce cascading effects with implications for ecosystem stability and associated services. Conserving Amazonian migratory fishes requires a broad portfolio of research, management, and conservation actions, within an ecosystem‐based management framework at the basin scale. This would require trans‐frontier coordination and recognition of the crucial importance of freshwater ecosystems and their connectivity. Existing areas where fishing is allowed could be coupled with a chain of freshwater protected areas. Management of commercial and subsistence species also needs fisheries activities to be monitored in the Amazonian cities and in the floodplain communities to allow assessments of the status of target species, and the identification of management units or stocks. Ensuring that existing and future fisheries management rules are effective implies the voluntary participation of fishers, which can be achieved by increasing the effectiveness and coverage of adaptive community‐based management schemes.

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“…An application of a multivariate time‐series technique to investigate intra‐annual and interannual dynamics and long‐term trends in fish catch for the 10 most abundant fish species in the Madeira River by Lima, Kaplan, and Rodrigues da Costa Doria (2017) showed that the best explanatory variables were maximum water level, flooding duration, previous year's flow, and rate of change in flow with species‐specific responses to these hydrological variables. More specifically, Castello, Bayley, Fabré, and Batista (2019) examined the abundance and catch of Colossoma macropomum , a long‐lived fish, and found that inundation positively and non‐linearly affected abundance of the age‐1 cohort, but not of older age classes, and did not find flooding effects on total catch. Of particular importance was the expansion and contraction of the ATTZ, because it provides habitat and rich food sources.…”

Section: Implications For Aquatic Conservation Of Hydrological Conditions and Changesmentioning

confidence: 99%

Amazon floodplain hydrology and implications for aquatic conservation

Mélack

Coe

2021

Aquatic Conservation

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The amplitude, duration, frequency, and predictability of runoff and inundation of aquatic habitats are key hydrological characteristics linked to aquatic ecosystem functioning and biodiversity, but they are seldom integrated into analyses of Amazon floodplain ecology. Remote sensing approaches, measurements and modelling of floodplain hydrology provide a basis for this integration. Effective legislation to protect floodplains and other wetlands depends on operational definitions that require application of hydrological data. Extent and changes of flooded areas are linked to fish diversity and to presence and growth of flooded forests and floating plants. Dam construction reduces river system connectivity and modifies the flood pulse, with major negative implications for floodplain ecosystems adapted to and dependent on a natural flood regime. Trends and variability in climate plus deforestation are altering the Amazon's hydrological cycle, causing changes in discharge and flooded area with concomitant ecological impacts.

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Flooding effects on abundance of an exploited, long-lived fish population in river-floodplains of the Amazon

Cited by 37 publications

References 46 publications

Tough fishing and severe seasonal food insecurity in Amazonian flooded forests

Tough fishing and severe seasonal food insecurity in Amazonian flooded forests

Conservation of migratory fishes in the Amazon basin

Amazon floodplain hydrology and implications for aquatic conservation

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